In the related art, examples of a lamp apparatus using a light-emitting element include, for example, a flat-type lamp apparatus using a GX53-type cap. The lamp apparatus of this type includes a housing opening in the direction of irradiation of a light beam and having a cap on the side opposite from the direction of irradiation of the light beam, and a light-emitting module having a light-emitting element and a lighting circuit configured to light the light-emitting element are accommodated in the housing.
In such a lamp apparatus, the light-emitting module is arranged on an inner surface of the cap in the innermost side in the housing so that a light beam generated by lighting of the light-emitting element of the light emitting module is radiated from the opening side of the housing. Also, by causing an outer surface of the cap to come into contact with the side of a luminaire in a state in which the lamp apparatus is mounted on the luminaire, heat generated when lighting of the light-emitting element is radiated by heat conduction from the cap toward the luminaire.
However, in the lamp apparatus having the light-emitting module mounted on the inner surface of the cap, the light-emitting module is positioned on the innermost side in the housing. Therefore, luminous intensity distribution is limited to a narrow angle and a wide angle of the luminous intensity distribution can hardly be achieved, and hence flexibility of luminous intensity distribution control is low.
In contrast, if the thickness of the entire cap is simply increased and the light-emitting module is positioned on the side of the opening of the housing, the lamp apparatus unfavorably grows in mass.
The problem to be solved by the embodiments described herein is to provide a lamp apparatus which achieves improvement of flexibility of luminous intensity distribution control and alleviate an increase of mass without lowering a heat radiation performance and a luminaire using such a lamp apparatus.